Gemini with Makersuite

[TuanaCelik]

This is the first go at implementing Gemini support with Makersuite. Works with:

gemini-pro for just text
gemini-pro-vision for text + image
GeminiChatGenerator for function calling

Needs:

• name changes
• docstrings
• tests

Contains: example.ipynb witn text generation on it's own, with images, and function calling

[TuanaCelik]

PS: Adding the function calling support with these packages was a bit fiddly and the documentation for Gemini suggests that this is still experimental and in beta. So up to you whether you want to keep it or not

[annthurium]

do we direct readers to the docs for more information? I've noticed there are often more comprehensive code samples over there (and I agree it would be a pain to maintain them everywhere, especially for haystack core integrations.

[silvanocerza]

I added some tests and related workflow, refactored the serialization of the components and also renamed them by prefixing them with GoogleAI. We're also going to rename the one in google-vertex-haystack with the VertexAI prefix to keep them in line with these components.

Most noticeable change is the rename of the package from gemini-haystack to google-ai-haystack. Better to be generic in this case, we don't know if Google is going to release other models or something different.

I also renamed the integration folder name to use underscores or the release process wouldn't work.